Powder delivery device

ABSTRACT

Provided is a device for the dispensing of powders of the type in which a generated gas flow entrains the powder to be dispensed and carries the powder from the device via a barrel. The barrel has a bore including a main portion with a continuous internal surface, and is characterized in that the length of the main portion is at least fifteen times its maximum internal diameter; and/or the internal bore of the main portion is tapered; and/or the barrel has an outwardly flared outlet portion.

TECHNICAL FIELD

This invention relates to improvements in a device for the dispensing ofpowder. In particular, the invention relates to an improvement indevices of the general type disclosed in International PatentApplication WO2010/070333 (which is hereby incorporated by reference).Such devices are of particular utility in surgical procedures or othermedical applications, for the topical delivery of powder to an internalor external surface of the body.

BACKGROUND

In devices of the type disclosed in WO2010/070333, a flow of gasentrains powder that is to be dispensed and carries that powder out ofthe device via a barrel. The barrel serves to direct the powder to thedesired application site. In the devices illustrated in WO2010/070333,the barrels are rather short and are of simple construction.

BRIEF SUMMARY

It has now surprisingly been found that the performance of devices ofthe type disclosed in WO2010/070333 may be substantially improved bymodifications to the design of the barrel. In particular, elongation ofthe barrel and/or the incorporation of certain structural features inthe internal bore of the barrel lead to improvements.

Thus, according to the invention there is provided a device for thedispensing of powder, the device being of the type in which a generatedgas flow entrains the powder to be dispensed and carries the powder fromthe device via a barrel, the barrel having a bore including a mainportion with a continuous internal surface, characterized in that:

(a) the length of the main portion is at least fifteen times its maximuminternal diameter; and/or

(b) the internal bore of the main portion is tapered; and/or

(c) the barrel has an outwardly flared outlet portion.

The device according to the invention is advantageous in that the formof the barrel may lead to certain improvements in performance. Inparticular, the form of the barrel may be chosen in such a way that theshape of the plume of powder emitted from the device is optimised for aparticular application. Thus, the distribution of powder on the intendedsite of application may be made more uniform. In addition, the velocityof the powder plume may be increased, and this may result in the form ofthe plume being maintained over greater distances, so that the powderplume remains intact when projected over larger distances than thoseobtained with a conventional device, enabling the powder delivery deviceto be held a greater distance from the desired delivery site. This maybe advantageous, for instance, in surgical procedures where it may notbe possible to hold the device close to the intended site of applicationof the powder. In addition, fall-off of powder from the plume, under theinfluence of gravity, may be reduced, leading to reduced deposition ofpowder at undesired locations. In addition, the outlet may be less proneto clogging, improving performance and reducing the maintenancerequired. Dispersion of the powder as it leaves the device may also beimproved. In general, the device according to the invention may operateeffectively over a wide range of gasflow pressures, e.g., from about 0.5bar to about 7 bar, though for most applications pressures in the range0.5 bar to 2 bar are generally satisfactory, e.g., from 0.5 bar to 1.5bar.

In some preferred embodiments of the device, the length of the mainportion is at least fifteen times its maximum internal diameter; and theinternal bore of the main portion is tapered.

In other embodiments of the device, the barrel has an outwardly flaredoutlet portion.

In some particularly preferred embodiments of the device:

(a) the length of the main portion is at least fifteen times its maximuminternal diameter; and

(b) the internal bore of the main portion is tapered; and

(c) the barrel has an outwardly flared outlet portion.

In embodiments in which the barrel is elongated, the barrel may be rigidor it may be flexible.

In rigid embodiments, the length of the main portion of the barrel is atleast fifteen times, e.g., at least eighteen times or at least twentytimes, its maximum internal diameter, or more.

In rigid embodiments, the length of the main portion is typicallybetween about 30 mm and 100 mm, e.g., about 50 mm or about 75 mm. Themaximum internal diameter of the main portion is typically from 1 mm to6 mm, e.g., about 2 mm or about 3 mm.

In flexible embodiments of the barrel, the barrel is generally longerthan for rigid embodiments, the length of the main portion of the barreltypically being between about 50 mm and about 300 mm, more commonlybetween about 50 mm and about 200 mm, and typically between about 100 mmand 180 mm, e.g., about 150 mm. The internal diameter of the barrel insuch embodiments is most commonly between about 1 mm and about 6 mm,typically between about 1.5 mm and about 4 mm, e.g., about 2 mm or about3 mm.

In order for the barrel to be flexible, its main portion is typicallyformed as a plastics tube, the plastics material being such that thetube may be manually deformed to the required shape without occlusion ofthe internal bore. The nature of the required shape will generally bedictated by the circumstances of the procedure in which the device isbeing used. Most commonly, a single bend may be introduced into thebarrel by the user of the device, but in other situations it may benecessary to form the barrel into a more complex shape, e.g., with adouble bend (i.e. an “S”-shape or the like). It has surprisingly beenfound that, even when bent into shapes as extreme as are ever likely tobe required in practice (e.g., two 90° bends), the pattern of powderdispensed from the device can remain satisfactory in terms of thegeometry of the plume of powder emerging from the distal end of thebarrel and the pattern of deposition of the powder.

The nature of the plastics material from which the flexible elongatebarrel is formed may be such that the tube retains the shape into whichit is deformed, at least for as long as is required during normal use.Preferably, however, the barrel incorporates one or more malleableelongate members that can be readily deformed, and which have the effectof retaining the barrel in the desired configuration until it is onceagain manually deformed to another configuration. Such members may takethe form of wires or rods of metal or other malleable material that areincorporated into the barrel. Most commonly, such wires or rods aredisposed parallel to the longitudinal axis of the barrel. In someembodiments, the main portion of the barrel is a tube having more thanone lumen, one lumen (normally the one having the greatestcross-sectional area) constituting the bore of the barrel along whichpowder is dispensed, and at least one lumen accommodating one or morewires or rods. In other embodiments, one or more wires or rods areembedded in the plastics material from which the barrel is formed. Theremay be just one such wire or rod, or there may be two, three, four ormore such wires. Where there is more than one wire or rod, those wiresor rods are most commonly equiangularly spaced around the main portionof the barrel.

Forms of material that are suitable for the malleable wires or rods arecopper wire and copper-coated steel wire. In one currently preferredembodiment, a single such wire is embedded in the wall of the tube thatconstitutes the main portion of the barrel. In other embodiments, two,three or four such wires may be used.

In other embodiments, another form of malleable material may be used toenable the form of the barrel to be altered. For instance, the mainportion of the barrel may be provided, along the whole or part of itslength, with a sheath of material that holds its shape when deformed,e.g., a foam material of the type known as memory foam or visco-elasticfoam.

In embodiments in which the internal bore of the main portion istapered, the internal diameter of the bore may decrease from theupstream to the downstream end of the main portion, i.e., the internalbore of the main portion may converge. Alternatively, the internaldiameter of the bore may increase from the upstream to the downstreamend of the main portion, i.e., the internal bore of the main portion maydiverge. The taper angle may typically be in the range 0.5° to 3°, morecommonly 0.5° to 2°.

Embodiments in which the main portion of the barrel is flexibletypically have a main portion that is considerably longer than is thecase for rigid embodiments. Those flexible embodiments are typicallyformed by extrusion and in such cases will therefore have an internalbore of constant cross-section. Embodiments in which the main portion ofthe barrel is rigid are more commonly formed by injection moulding, inwhich case the internal bore of the main portion of the barrel may havea uniform cross-section or may, more preferably, be tapered.

In embodiments in which the barrel has an outwardly flared outletportion, the outlet portion typically has a length of between 5 mm and25 mm, more commonly between 5 mm and 10 mm. The internal diameter ofthe outlet portion may increase from its upstream to its downstream endby a factor of two or more. As will be readily appreciated, where theoutlet portion is “flared”, that term refers to the internal shape ofthe outlet, i.e., to a widening of the outlet from its upstream to itsdownstream end. That widening may or may not be reflected in theexternal shape of the outlet.

Apart from the modifications to the barrel described above, the deviceaccording to the invention may be as described in WO2010/070333, inparticular in relation to FIGS. 3 to 12 of that document. Brieflysummarised, such a device has a main body that may comprise upper andlower housing components formed in plastics material by injectionmoulding. The main body may have the general form of an elongatecylinder that is adapted to be held in a user's hand, the underside ofthe lower component being shaped to facilitate such grip. A pushbutton-type actuator may be mounted in the top of the main body suchthat, when the device is held by the user, the actuator can be depressedby the thumb of the hand that holds the device. A flexible tube mayextend from the rear end of the device and may be adapted to beconnected to a gas source, e.g., a source of compressed air. A connectormay be provided at the distal end of the tube. A vial containing thepowder that is to be dispensed from the device may be coupled to thedevice, e.g., via an upstanding spigot that is received within the mouthof the vial. The barrel may extend from the front end of the device.

The barrel may be provided with a mounting that enables its orientationrelative to the main body of the device of which it forms part to bevaried. For instance, the barrel may engage the main body of the devicein the manner of a ball-and-socket connector, so that the orientation ofthe barrel may be adjusted, e.g., manually by the operator.

In presently preferred embodiments, however, the barrel is connected tothe main body of the device in a fixed orientation. The barrel may beconnected to the main body by a threaded connection, or by a suitablequick release connection such as a bayonet fitting. Other forms ofconnection may alternatively be used, e.g., a luer lock-type connection,or an interference fit or the like.

The device according to the invention may be manufactured using medicalgrade materials, most components being most conveniently manufactured inplastics by techniques such as injection moulding and extrusion. Whereappropriate, components may be manufactured in other materials, e.g.,glass or metal.

The device according to the invention may be used to deliver a widevariety of powders to a surface of the body. Such powders include agentsintended to have a therapeutic effect, either in terms of apharmacological effect on the body or as disinfectants or the likeuseful in the prevention or treatment of infections. One particularfield in which the device of the invention is useful, however, is forthe delivery of haemostatic powder compositions to internal tissuesexposed during surgical procedures or after traumatic injury. Suchhaemostatic compositions, which may also be described as tissuesealants, may for instance comprise dry powder mixtures of fibrinogenand thrombin. Such a mixture is essentially inert when formulated in thedry state, but once hydrated, e.g., upon application to a bleedingwound, the mixture leads to the production of fibrin which cross-linksto form a blood clot.

Thus, according to a further aspect of the invention, there is provideda method of delivering a haemostatic composition to an internal tissueexposed during surgical procedures or after traumatic injury, whichmethod comprises providing a device as described above, which device ischarged with a quantity of a haemostatic composition in dry powder form,and dispensing said composition from said device onto said tissue.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described in greater detail, by way ofillustration only, with reference to the accompanying drawings, inwhich:

FIG. 1 is a perspective view of a first embodiment of a powder deliverydevice according to the invention;

FIG. 2 is a side view of the device of FIG. 1;

FIG. 3 shows a barrel that forms part of the device of FIG. 1;

FIG. 4 is a cross-sectional view of the barrel of FIG. 3;

FIGS. 5( a) and (b) illustrate the range of vertical movement of thebarrel;

FIGS. 6( a) and 6(b) illustrate the range of lateral movement of thebarrel;

FIG. 7 is a perspective view of a second embodiment of a powder deliverydevice according to the invention, showing the barrel separated from themain body of the device;

FIG. 8 is a perspective view from behind of the barrel of the device ofFIG. 7;

FIG. 9 is a cross-sectional view of the barrel of FIG. 8;

FIG. 10 is a perspective view of a third embodiment of a powder deliverydevice according to the invention, comprising the main body of thesecond embodiment with an alternative form of barrel attached to it;

FIG. 11 is a perspective view of the barrel shown in FIG. 10; and

FIG. 12 is a cross-sectional view of the barrel of FIG. 11.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring first to FIGS. 1 and 2, a first embodiment of a powderdelivery device in accordance with the invention is generally designated20. Save for the inventive modification described in greater detailbelow, the device 20 is of similar form to the device illustrated inFIGS. 3 to 12 of WO2010/070333. Briefly summarised, the device 20 has amain body that comprises upper and lower housing components 23 a, 23 bthat are formed in plastics material by injection moulding. The mainbody has the general form of an elongate cylinder that is adapted to beheld in a user's hand, the underside of the lower component 23 b beingshaped to facilitate such grip. A push button-type actuator 27 ismounted in the top of the main body such that, when the device 20 isheld by the user, the actuator 27 can be depressed by the thumb of thehand that holds the device 20.

A flexible tube 25 extends from the rear end of the device 20 and isadapted to be connected to a gas source, e.g., a source of compressedair (not shown). A suitable connector 26 is provided at the distal endof the tube 25.

A glass vial 31 is coupled to the device 20 via an upstanding spigot(not visible) that is received within the mouth of the vial 31. A pairof clips 35 engages with a peripheral lip of the vial 31, so as to holdit securely in place. In other embodiments, the vial 31 may simplyengage the spigot or similar formation with an interference fit and/orthe spigot or similar formation may have a degree of resilience enablinga clip-type fitting to the vial. To facilitate sealing engagement of thevial 31 with the device 20, the formation that receives the mouth of thevial 31 may incorporate or be formed from a suitable elastomericmaterial (e.g., a thermoplastic elastomer). A device 20 having such afitting may be produced using a two-shot molding process.

As for the device described in WO2010/070333, the front end of thedevice 20 is provided with a tubular barrel 29, through which powder isdispensed from the device 20. The barrel 29 in the present invention,however, is rather different in form to that described in the earlierpatent application, as is discussed in greater detail below.

The base of the spigot with which the vial 31 is engaged is closed by aperforated plate, such that when the device is in the operativeorientation shown in FIGS. 1 and 2, powder contained within the vial 31rests upon the perforated plate. When the actuator 27 is depressed, gasis caused to flow through the device 20, as described in WO2010/070333.The flow of gas has two, related, effects. First, the gas flow drives amechanical agitator in the form of a ball that is held captive within acircular track; rotation of the ball around the track induces vibrationsin the device 20, the effect of which is to dislodge powder from thevial 31, through the perforated plate that constitutes the base of thespigot that is engaged by the vial 31. Secondly, a proportion of the gasflow is directed at the underside of the perforated plate, entrains thepowder that is dislodged from the vial 31 and carries it from the device20 via the barrel 29.

Thus, to dispense powder from the device 20, the user holds the device20 in one hand, directs the barrel 29 at the intended site ofapplication of the powder, and depresses the actuator 27 with the thumb.This permits gas to flow through the device 20, causing the ball torotate rapidly around the track and inducing a degree of mechanicalvibration that is transmitted to the vial 31. Most of the gasflow isvented from the device 20. However, a small proportion of gas isdirected at the underside of the perforated plate. The mechanicalagitation of the device 20 caused by rotation of the ball within thetrack facilitates the release of powder from the vial 31. The powder isentrained in the flow of air that escapes from the device 20 via thebarrel 29. The powder is blown out of the device 1 and deposited on thesite of application.

As noted above, the device 20 differs from that disclosed inWO2010/070333 in the form of the barrel 29. The barrel 29 is shown inFIGS. 3 and 4.

As can be seen in FIG. 3, the barrel 29 is elongate and of circularcross-section, extending from a ball-type connector 291 at one end to aflared outlet 292 at the other. The ball-type connector 291 iscaptivated within an opening at the front of the main body of the device20, between the upper and lower housing components 23 a, 23 b, in themanner of a ball-and-socket joint.

As can be seen from FIG. 4, the barrel 29 has an internal bore having anentry portion 293 that is of constant diameter, a main bore 294 that isof reduced diameter relative to the entry portion 292, and an outletportion 295 within the flared outlet 292. The diameter of the main bore294 reduces along its length.

The overall length of the barrel 29 is approximately 70 mm. The entryportion 293 of the internal bore has a diameter of approximately 5 mmand a length of approximately 8 mm. The diameter of the main bore 294,which has a length of approximately 48 mm, reduces from approximately3.5 mm adjacent the entry portion 293 to approximately 2 mm where themain bore 294 meets the outlet portion 295. The angle of convergence ofthe internal wall of the main bore 294 relative to its longitudinal axisis thus approximately 1°.

The entry portion 293 receives a tube (not visible in the drawings) bywhich the gasflow and entrained powder are fed from the main body of thedevice 20 to the barrel 29.

The narrowing of the main bore 294 may cause an increase in velocity ofthe gasflow as it exits the device 20 and, together with the flared formof the outlet portion 295, this may help to maintain the shape of thepowder plume emitted from the device 20, resulting in good coverage ofthe application site with powder. Fall off of powder from the emittedplume, under the influence of gravity, may be reduced, minimising theamount of powder that is dispensed onto sites other those to which thepowder is intended to be delivered. The flared form of the outletportion 295 also leads to a reduced likelihood of clogging.

In this embodiment, directional control over the emitted powder isachieved by virtue of the fact that the ball-type connector 291 permitsthe orientation of the barrel 290 relative to the main body of thedevice 20 to be varied over a wide range, both vertically (see FIGS. 5(a) and 5(b)) and laterally (FIGS. 6( a) and 6(b)).

Turning now to FIG. 7, a second embodiment of a powder delivery deviceaccording to the invention is generally designated 30. The device 30 isbroadly similar to the first embodiment 20 described above in that itcomprises a main body 123 that receives vial 131 of powder. In thisembodiment, the vial 131 is received within a ring 137 of thermoplasticelastomer that is molded onto the upper component of the main body 123in a two-shot molding process.

Like the first embodiment 20, the device 30 comprises a tubular outletbarrel 39. In the second embodiment 30, however, the barrel 39 connectsto the main body 123 by means of a bayonet fitting and has a fixedorientation relative to the main body 123.

As can be seen in FIG. 8, the face of the barrel that abuts the mainbody 123 is formed with a male bayonet spigot 391 with a central recessthat receives the open end of a tube 135 (see FIG. 7) by which thegasflow and entrained powder are fed from the main body 123 of thedevice to the barrel 39. The barrel 39 is injection moulded in rigidplastics material (eg ABS) and (referring to FIG. 9), like the barrel 29of the first embodiment 20, is formed with an internal bore 394 thatdiminishes along its length (in this case from an internal diameter ofapproximately 2.9 mm to an internal diameter of approximately 2 mm). Thebarrel 39 has a flared outlet 392.

As for the first embodiment 20, the narrowing of the main bore 394 maycause an increase in velocity of the gasflow as it exits the device 30and, together with the flared form of the outlet 392, this may help tomaintain the shape of the powder plume emitted from the device 30,resulting in good coverage of the application site with powder. Fall offof powder from the emitted plume, under the influence of gravity, may bereduced, minimising the amount of powder that is dispensed onto sitesother than to which the powder is intended to be delivered. The flaredform of the outlet 392 also leads to a reduced likelihood of clogging.

Finally, FIG. 10 depicts a third embodiment of a powder delivery deviceaccording to the invention, which is generally designated 40. Thisembodiment differs from the second embodiment 30 solely in the form ofthe outlet barrel 49. Indeed, the outlet barrel 39 of the secondembodiment 30 and the outlet barrel 49 of the third embodiment 40 areinterchangeable.

The form of the barrel 49 is shown in greater detail in FIGS. 11 and 12.The barrel 49 comprises three components: a bayonet hub 491, a flexibleplastics tube 492 and an outlet tip 493.

The bayonet hub 491 is injection moulded in rigid plastics material(e.g., polyamide) and corresponds in overall shape to the proximal endof the rigid barrel 39 of the second embodiment 30. It has a centralbore 495 that terminates in a socket within which one end of theflexible tube 492 is received. That end of the tube 492 may be fixed tothe hub 491 by adhesive, by ultrasonic welding or by any other suitablemeans. The other end of the tube 492 is received within a similar socketformed in the outlet tip 493 (which is also formed by injection mouldingof a suitable material, e.g., polyamide) and may be fixed by similarmeans. The distal (downstream) part of the outlet tip 493 has a flaredinternal bore.

The flexible tube 492 is formed by extrusion in polyurethane, acopper-coated steel wire 494 being embedded in the wall of the flexibletube 492 during manufacture. A user of the device may therefore form theflexible tube 492 into a desired configuration, the effect of the wire494 being to retain the tube 492 in that configuration during use. Thethird embodiment 40 may be particularly useful in surgical procedures inwhich it is desired to deposit the powder onto surfaces that are hiddenand at which a straight barrel cannot be directed.

1. A device for the dispensing of powder comprising: a barrel having abore including a main portion with a continuous internal surface throughwhich a generated gas flow entrains the powder to be dispensed, wherein:a length of the main portion is at least fifteen times a maximuminternal diameter of the bore; and the barrel has an outwardly flaredoutlet portion.
 2. (canceled)
 3. (canceled)
 4. A device as claimed inclaim 1, wherein the internal bore of the main portion is tapered.
 5. Adevice as claimed in claim 1, wherein the barrel is rigid.
 6. A deviceas claimed in claim 5, wherein the length of the main portion of thebarrel is at least eighteen times or at least twenty times the maximuminternal diameter of the bore.
 7. A device as claimed in claim 5,wherein the length of the main portion is between about 30 mm and 100mm.
 8. A device as claimed in claim 5, wherein the maximum internaldiameter of the main portion is from 1 mm to 6 mm.
 9. A device asclaimed in claim 1, wherein the barrel is flexible.
 10. A device asclaimed in claim 9, wherein the main portion of the barrel has a lengthof between 50 mm and 300 mm.
 11. A device as claimed in claim 9, whereinthe internal diameter of the barrel is between 1 mm and 5 mm.
 12. Adevice as claimed in claim 9, wherein the main portion of the barrelcomprises a plastic tube.
 13. A device as claimed in claim 12, whereinthe barrel incorporates one or more malleable elongate members.
 14. Adevice as claimed in claim 13, wherein the elongate malleable membersare wires or rods.
 15. A device as claimed in claim 14, wherein thewires or rods are embedded in the plastic material from which the barrelis formed.
 16. A device as claimed in claim 14, wherein the one or moreelongate malleable members are one or more copper or copper-coated steelwires.
 17. A device as claimed in claim 1, wherein the internal diameterof the main portion decreases from an upstream end to a downstream endof the main portion.
 18. A device as claimed in claim 1, wherein theinternal diameter of the main portion increases from an upstream end toa downstream end of the main portion.
 19. A device as claimed in claim1, wherein the internal diameter of the main portion increases from anupstream end to a downstream end of the main portion or decreases fromthe upstream end to the downstream end of the main portion at a taperangle of 0.5° to 3°.
 20. A device as claimed in claim 1, wherein theoutlet portion has a length of between 5 mm and 25 mm.
 21. A device asclaimed in claim 20, wherein an internal diameter of the outlet portionincreases from an upstream end to a downstream end by a factor of two ormore.
 22. (canceled)
 23. A device as claimed in claim 1, wherein thebarrel is provided with a mounting that enables an orientation relativeto the main body of the device of which it forms part to be varied. 24.A device as claimed in claim 23, wherein the mounting is aball-and-socket connector.
 25. A device as claimed in claim 1, whereinthe barrel is connected to the main body of the device in a fixedorientation.
 26. A device as claimed in claim 25, wherein the barrel isconnected to the main body of the device by a bayonet fitting.
 27. Amethod of delivering a haemostatic composition to an internal tissueexposed during surgical procedures or after traumatic injury, whichmethod comprises providing a device as claimed in claim 1, which deviceis charged with a quantity of a haemostatic composition in dry powderform, and dispensing said composition from said device onto said tissue.